#include <iostream>
#include <unordered_set>

template <typename T>
void Print(const T &v)
{
    for (auto ite = v.begin(); ite != v.end(); ite++)
    {
        std::cout << *ite << " ";
    }
    std::cout << std::endl;
}

int main()
{
    std::unordered_set<int> s;
    s.insert(2);
    s.insert(1);
    s.insert(3);           

    auto ite = s.find(2);
    std::cout<<*ite<<std::endl; 
    s.erase(1);                                           
    Print(s);

    return 0;
}